Seal for overlapping metal bands



'|. w. GIRVAN SEAL FOR OVERLAPPING METAL BA ND S 2 Sheets-Sheet 1 Filed Feb. 9 1938 6 fr van L o T N m am v Q. W n a w k 'Y wAw-r'v.

|. WQGIRVAN 2.199.198

SEAL FOR OVERLAPPING METAL BANDS April 30, 1940.

Filed Feb. 9, 1938 ZSheets-Sheet 2 *KL'ATT'Y Apr. so, 1940 I PATENT oFFica I 2,199,190; I SEAL FOR ovnamrrmc smrsl. mums Ian Waverley Girvan, 8 Application February 9,

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1m, Serial so sam In GreatBritainNovember alas-1- This invention relatesto animproved seal for overlappins metal bands, such as are used for strapping boxes, cases and the like. I One object of they present invention is to pro- '51 vide a band seal of the. type described which includes a-tension lock, as well asa facelock.

Another object is to produce a band seal which does not. involve the provision of upstanding freeended tongues.

Still another object of. the invention is to pro vide a band seal in which the band is not weakenedby any transverse cuts.

- According to the invention, these and other objects which will appear more clearly asthe u specification. proceeds, are accomplished by the arrangements set forth in the following detailed description, defined in the appended claims, and i illustratively exemplified in the accompanying drawinga'in which:

90 Figure 1 is a plan view of the overlapped'parts i of the metal band strap, showing one embodiment of the present invention.

Figure 2 isaside elevation of the overlapped parts of the band according to Fig. 1, before the sealing movement. 7

Figure 3 is a plan view of the overlapped parts of the band according to Fig. 1 after. the same have beenmutually displaced to produce the seal.

. Figure 4 is a plan view of the overlapped parts 30 of a modified form of the invention.

Figure 5 is a side elevation of the band according to Fig. 4, before the sealing movement.

Figure 6 is an enlarged plan view ot-the parts of the band in the embodiment of Fig. 4 showing 35 the same in the position which they assume when they have been mutuallydisplaced to produce the seal. a

Figure 'l is a plan of a further modification. I Figure 8 is a plan viewoi the overlapped parts of the band showings. still further modification of the invention. a Figure 9 is'aslde elevation of the band according to Fig. 8, before the sealing movement has occurred;

' I Figure 10 is a plan view, on a larger scale, of the form shown in Figure 8, illustrating the relative position of the parts after relativemovement between the overlapped parts of the bandhas taken place, I

Figure 11 is a plan view of the overlapped ends of the band showing a further form of the present invention. I

Figure 12 is'a side elevation of this form of the invention showing the parts of the ends of the view of the overlapped parts I I of theband strap, the slits converging towards I one another to a point or closest approach i8 40 band before the sealing movement has taken place..

Figure 13 is plan view showing the completed I I seal provided by this form of the present invention, and

. 6 Figure 1 1 is a section on line M-H of Figure 13 illustratingthe"face-lock eiiect which is secured by means of this arrangement. I It must be clearly understood that the present invention is not limited to any particular con- 10 struction or form of sealing machine. The slits may be cut and the tension on the band released (or relative movement of the overlapped parts of the band caused in any other way) by means of any suitable construction of machine whether it l5 be operated by one or two levers. Referring first to Figures 1 to 3 of the accompanying drawings, I. and il represent respectively the upper and lower parts of the overlapped ends of a metal band strap encircling a go packing case or other article to'bev strapped (not shown). The band, in eflecting the seal, is first placed under tension to 'any desired degree by means of a strapping machine of any suitable construction. The encircling metal band having been placed under the required tension, there is cut therein by means of suitable dies in the strap- I ping machine a plurality of pairs of individually independent slits. Any desired number of pairs of identical slits may be out without departing from the scope of the present invention but it is believed that threesuch pairs of slits will be quite sufiicient togive an efiicient and effective seal for all normal purposes.

Each pair of slits is identical and so only a single pair and the; operation of the same will be described. Each pair of slits comprises a part iii inclined at an acute angle to the marginal border after which they are continued parallel to one another or, as shown in the drawings, diverging :i'rom one another as at I4. The actualshape or mutual relation'otthe continued-part ll ,oi-the slits is immaterial in carrying out the present 4 I invention. They may, as above stated. even' parallel with one another, all that is necessary 'is um this continuation of the slits shall; be such I I that it'tacilitat'es the relative movement 01' the overlapped parts II and H of the band, as hereso inafter described.

That part ,llsoizthe overlapped parts .01 the hand between the ,sllts "and i4 is displaced. preferably'though not essentially at the same time .as the-slits are-cut, downwardly from the g plane of the overlapped parts of the band in such a manner that, at the point l3 of closest approach of the mutually converging slits l2 the upper surface of the upper band I0 is moved below the under surface of the under band ll, whilst at the point "5 of widest separation of the slits l2 the under band is not displaced. The continuation or extension Id of the slits l2 facilitates this special displacement as will be readily appreciated from Figure 2.

It may be pointed out here that instead or the part l5 of the ends it! and ll of the band being displaced downwardly, they may equally well be displaced upwardly without departing from the scope of the present invention. Two advantagesare, however, secured by displacing this part of the ends of the band downwardly. In the first place, there will be no projections whatsoever from the upper surface of the upper band I 0 and, in the second place, since there will be a tendency for the band to bind on to the tapering dies, it will be easier to free the same when the upper male die moves.

If it be assumed that the dies which'are adapted to cut the slits l2 and their extensions I 4 are also adapted to displace the band between the slits then, after the slits have been cut, the relative positions of the overlapped parts of the band is that shown in plan in Figure 1 and in side elevation in Figure 2. It shouldbe particularly noted that the method of sealing according to the present invention does not necessarily involve the vertical displacement of the margins l6 of the overlapped parts of the band.

After the slits have been cut and the parts of the overlapped ends of the band depressed as described above, the tension on the band is released, for example, by severing the encircling band from the stock coil, whereupon relative movement of the two parts of the band takes place in the direction of the arrows shown in Figure 2. The parts thereupon take up the position shown in Figure 3.

Since that part of the upper band l8 between the mutually converging slits I2 has been pressed down completely through the corresponding part of the under band I I (see Figure 2), it will be appreciated that when relative movement between the upper end of the band and the lower end of the band takes place in the direction of the arrows shown in Figure 2, the converging edges of the part l5 of the upper band ll! between the slits l2 will engage with and even bite into the corresponding edges of the slits in the margins of the under band H to give a transverse bite or seal, the effective value of which increases proportionally to the amount of movement which takes place between the upper and lower parts l0, and II of the band. Any eflort to separate 4 the overlapping parts of the band still further in this direction will, therefore, tend to increase the transverse bite or seal between the overlapping parts of the band. It is ,for this reason that I referto the main looking or sealing action of the arrangement according to the present invention as a tension-lock.

It follows that since the part I5 of the upper band moves relative to the corresponding part of the under band the edges will, to a certain extent, overlap as shown in the shaded portions l8 of Figure 3. At these parts I8 there is a portion of the upper band underlying and overlap- -ping the under band thus giving a-face-lock which will prevent the easy separation oi. the overlapped parts of the band in a vertical direction. With the construction shown in Figures 1 to 3 this face-lock is comparatively small and it is for this reason that certain of the construcpossibility of separating the overlapping parts ill and H of the band vertically, i. e., the desirebility of. providing an adequate face-lock. Whilst, therefore, it is obvious that the greater the angle of convergence between the slits 12 the greater will be the tension-lock secured, it must be remembered that by just so much as the angle of convergence is increased, so, with the arrangement illustrated in Figures 1 to '3, will the efiective face-lock against vertical displacement be decreased. This is due to the decreased effective overlap of the displaced parts, as will be readily understood. This overlap is shown by means of the shaded parts H3 in Figure 3 and the same will obviously be controlled by the extent of the movement which takes place when the tension is released. This in turn is obviously controlled by the angle of convergence of the slits 92. For this reason I have found it to be of benefitto limit the angle of convergence to the slits I2 to form 5 to 15$ The less the angle of convergence between the slits l2 the greater will be the edge surface entering into the mutual engagement to give what I have referred to above as the tension lock, i. e., a lock which increases as the tension of the overlapping parts of the band increases in the direction of the arrow shown in Figure 2. But, as above. stated, due account must be taken of the face-lock or ability to prevent vertical after, need be straight; they may be curved to any comparatively large radius or other suitable shape as desired.

A more effective face-lock may, however, be secured by means of the modification of the shape of the slits as shown in Figures 4 to 6 of the accompanying drawings. In this construction the same slits l2 mutually converging are provided as in the construction shownin Figures 1 to 3, but instead of immediately communicating with the diverging slits l4 the same are inclined more sharply as at 20 then round as at 2l to diverging slits 22 and are finally continued as parallel slits 23, these parallel slits serving to facilitate the relative movement of the overlapped parts of the band. I

The construction illustrated in Figures 4 to 6 has also the advantage that it will facilitate the manufacture of the dies necessary to cut the may be of any slits and to displace the parts of the band between the slits. Otherwise the tension-lock secured is the same assuming the included angle between invention. In this arrangement, elongatedslots effective overlap of the under and upper band which prevent separation of the overlapping parts of the band independent of the tension-lock" provided. The arrangement illustrated in Figures 4 to 6 differs from that illustrated in Figures 1 to 3 in so far as it provides an improved facelock which tends to prevent unauthorised vertical separation of the overlapping parts It) and -II of the band, and like reference numerals have been used to indicate like parts.

Figure 7 illustrates a slight modification of the shape of the slits shown in Figures 4 to 6. In this modification the mutually converging slits H! are, as shown in Figures 4 to 6. continued as more sharply converging and curved-or straight parts and then continue as diverging parts which form, in effect, the chord to the part 22 and 23 shown in Figure 4. Otherwise the operation is the same.

Figures 8 to 10 illustrate a construction of strapping band-lock or seal which is, in effect, a

- duplicate of the seal, illustrated in Figures 1 to 3.

In this arrangement the converging slits l2 of each pair of slits are merged into parallel portions 4! and are then continued for substantially the same distance as the parts f2 as a diverging pair of slits'42 (or what may be considered as an opposed pairof converging slits). 'The displacement of the metal between the converging and diverging slits l2 and 42 respectively is then opposed (upwardly and downwardly for example) and a double transverse tension lock will be ob-- tained, as will be readily appreciated. Furthermore, counter transverse bites (Figure 10) will with such an arrangement be set up close to the apices of the obtuse angles 50 should it be at-' tempted to release the seal by means of a reverse movement of the overlapped parts of the band. Figures 11 to 14 illustrate a simple andvery strong form of seal according to the present -60 are cut in the overlapped parts ofthe band,

by semi-circular or other appropriately shaped indentations 6|. If desired, the indentations 6| may be formed as like projections extending into the margins of the band without departing from the scope of the present invention. It is also to be noted that, whilst, it is convenient to continue the slots on the narrower side (or right-hand side as shown in the drawings) of the indentations 6| as strict continuations of the slits 60 so that the slit as awhole is of yoke shape, the said continuations, which are designated by 62, correspond to thecontinuation slits M of Figures 1 to 3 and may accordingly be of any shape which will allow relative movement of the overlapped parts of the band without departing from the scope of the present invention.

The strip of thebands l0 and II defined by the slits 60, GI and 62 is displaced downwards (or upwards as above explained) so that the part SI of the one band'passes completely through the corresponding aperture in the other band (see I Figure 12, which shows vthe position of the parts before the relative movement has taken place). The tension is thereupon released and relative movement takes place. .'As far as the tensionlock? is concerned, the parts 60 of the slits .(and also the parts 62 it they form strict continuation of the slits 60).-correspond exactly to the I I slits not the arrangement illustrated in Figures 1 (:03 and give an effective tension-lock as explained in connection with the said construction.

It is, however, in connection with the face-lock secured that this arrangement is particularly advantageous." It will be seen, on reference to Figures 13 and 14 that the parts adjacent the following edge of the slit 6| in the upper band will become positioned under the marginal portions of the under band, as indicated by the'shaded parts 54 in Figure 13, to give a very effective face-lock.

Obviously the converging slits may be straight or curved as desired and as'iar as each pair is concerned-may be directly opposed transversely of the band or may be staggered along the length of the same as desired. It will be readily appreciated that the main sealing is obtained by means of the transverse bite between the two ends of the band and since the band at the material part is not'weakened byany transverse slit or cut a much lower quality of steel and/or a narrower band may be used than with prior constructions including free-ended tongues produced by transverse cuts.

In all cases, it should be clearly understood that the slits of each pair are quite independent of and do not communicate with one another in the seal according to the present invention.

- I claim:

1. In a seal for overlapping metal bands, two

superposed band portions provided with a pairof substantially longitudinal slits defining be tween them longitudinal strips integral at their ends with the respective bands, both said strips having midportions of reduced width bent out of the respective planes of their bandsto leave therein aligned openings having correspondingly restricted midportions, the strip out from one of said bands having its midportion'bent through the opening in the second band and onset beyond the plane of the same, and'both strips tapering into said midportions, whereby upon displacement of said first band relative to the second band in the direction of the taper, the tapering edges of the strip of the first bandat their intersections with the tapering edges of the opening in said second band effect a tension lock while simultaneously a wider sectionof the offset midportion of the stripof the first band comes to overlap the edges of the opening in the-second band at'said restricted midportion of said opening to provide a face lock. 2. A sealfor overlapping'bands, as claimed in claim 1, in which the tapering edges of. said strips converge towards one another at an angle between 5and 15.

3. A seal for overlapping bands, as claimed in I claim 1,'in which the tapering edges of said strips have outer portions converging towards one another at a smaller angle and inner portions converging towards one another at a greater angle.

4. A seal foroverlapping bands, as claimed in claim 1, in which each of said midportions comprises a section having parallel edges.

5. A seal for overlapping bands, as claimed in claim 1, in which each of said midportions comprises two longitudinally adjoining sections of substantially different widths. p IAN WAVENEY GIRVAN. 

